Lithium orthosilicate (Li4SiO4) is well suited for energy storage systems in concentrated solar power (CSP) generation due to its large energy storage density, and relatively low regeneration temperature. However, performance degradation over multiple storage/release cycles is an urgent problem to be solved prior to its application. In this work, the transition metal Nd was employed as a promoter to modify Li4SiO4 heat carriers, and the results demonstrated that the Li4SiO4 heat carrier doped with 9 wt% Nd2O3 (LA-9Nd) had an energy storage density of up to 680 kJ/kg at 650 °C with almost no attenuation over 10 cycles, which was attributed to the lattice defects and inert frameworks formed by the Nd doping. The energy storage performance of LA-9Nd was also tested under harsh conditions, where high CO2 concentration in the regeneration process deteriorated the carbonation performance of the heat carriers. In addition, to address the elutriation problem of Li4SiO4-based heat carrier powders during cyclic fluidization, water-graphite and agar-graphite granulation methods were used to granulate the LA-9Nd powders. The granulated pellets exhibited both good energy storage density and anti-attrition ability. In general, satisfactory energy storage density, cyclic stability and mechanical performance endow Nd-doped Li4SiO4 heat carrier pellets with great prospects for thermochemical energy storage.

中文翻译：

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Nd掺杂Li4SiO4颗粒热化学储能性能及造粒研究


正硅酸锂 （Li4SiO4） 由于其储能密度大且再生温度相对较低，非常适合用于聚光太阳能发电 （CSP） 中的储能系统。然而，在多个存储/释放周期内性能下降是一个亟待解决的问题。在本工作中，采用过渡金属 Nd 作为促进剂对 Li4SiO4 热载体进行改性，结果表明，掺杂 9 wt% Nd2O3 （LA-9Nd） 的 Li4SiO4 热载体在 650 °C 时的储能密度高达 680 kJ/kg，在 10 次循环中几乎没有衰减，这归因于 Nd 掺杂形成的晶格缺陷和惰性框架。LA-9Nd 的储能性能也在恶劣的条件下进行了测试，其中再生过程中的高 CO2 浓度使热载体的碳化性能恶化。此外，为解决 Li4SiO4 基热载体粉末在循环流化过程中的淘析问题，采用水-石墨和琼脂-石墨造粒方法对 LA-9Nd 粉末进行造粒。颗粒状颗粒表现出良好的储能密度和抗磨损能力。总体而言，令人满意的储能密度、循环稳定性和力学性能赋予了 Nd 掺杂 Li4SiO4 热载体颗粒在热化学储能方面的巨大前景。